The invention relates to methods for designing contact lenses. In particular, the invention provides a method for designing contact lenses in which the thickness in the lens periphery is precisely controlled.
The use of contact lenses for purposes of visual acuity correction and cosmetics is well known. It is important in the design of a contact lens to provide for good handling, comfort, centration, and orientation of the lens. Each of these lens characteristics is dependent to a large extent on the thickness profile of the lens periphery.
Conventional methods for controlling the thickness of the lens periphery include the use of one or more of lenticular zones, bevels, chamfers, and the like. However, these methods do not provide precise control of the thickness differential of the lens periphery. Additionally, these methods do not provide a means for designing a non-rotationally symmetric lens. Therefore, a need exists for a method for designing contact lenses that overcomes these disadvantages.